Borna disease is an infectious neurological disease that occurs sporadically in horses and sheep in Central Europe (Ludwig, Prog. Med. Virol. 35:107 (1988)). Brain homogenates from infected animals can be used to infect a large number of animal species from rodents to non-human primates (Carbone, Virol. 61:3431 (1987); Narayan, Science 220:1401 (1983); Sprankel, Med. Microbiol. Innumol. 165:1 (1978)). Studies in rats have shown that the agent is highly neurovirulent and invades the brain from peripheral sites by axonal transport (Carbone, supra). It replicates in specific groups of neurons in the cerebral cortex and causes biphasic behavioral disease characterized by aggression and hyperactivity during the acute phase of infection and apathy and eating disorders during the chronic stage (Narayan, supra). In tree shrews (Turpaia glis), infection is associated with disruption in social interactions (Sprankel, supra). In addition, recent studies demonstrate the presence of anti-Borna Disease Virus (BDV) antibodies in humans with psychiatric illnesses which include personality disorders and schizophrenia (Rott, Science, 228:755 (1985); Amsterdam, Arch. Gen. Psychiatry, 42:1093 (1985)).
The BDV virus replicates in cell cultures and rat brain with the synthesis of novel 38/39, 24 and 14 kD proteins (Haas, J. Gen. Virol. 67:235 (1986)). However, the virus has not been classified since neither a particle nor a specific nucleic acid has been identified in infectious material.